Add grpcserver test coverage

- Add comprehensive test file for internal/grpcserver package
- Cover interceptors, system, engine, policy, and auth handlers
- Cover pbToRule/ruleToPB conversion helpers
- 37 tests total; CA/PKI/ACME and Login/Logout skipped (require live deps)

Co-authored-by: Junie <junie@jetbrains.com>

web/templates/initializing.html

@@ -1,9 +1,16 @@
 {{define "title"}} - Initializing{{end}}
+{{define "container-class"}}auth-container{{end}}
 {{define "content"}}
-<h2>Initializing...</h2>
-<p>Metacrypt is being initialized. Please wait.</p>
-<div hx-get="/v1/status" hx-trigger="every 2s" hx-swap="none"
-     hx-on::after-request="if(JSON.parse(event.detail.xhr.responseText).state==='unsealed')window.location='/dashboard'">
-    <p>Checking status...</p>
+<div class="auth-header">
+    <div class="brand">Metacrypt</div>
+    <div class="tagline">Cryptographic Services</div>
+</div>
+<div class="card">
+    <div class="card-title">Initializing</div>
+    <p>Metacrypt is being initialized. This will only take a moment.</p>
+    <div hx-get="/v1/status" hx-trigger="every 2s" hx-swap="none"
+         hx-on::after-request="if(JSON.parse(event.detail.xhr.responseText).state==='unsealed')window.location='/dashboard'">
+        <p style="color: var(--f2); font-size: 0.875rem;">Waiting for service to come online&hellip;</p>
+    </div>
 </div>
 {{end}}